Packing material for lithium cell and production method thereof

Abstract

A packing material for a lithium cell of the present invention includes a first adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer or a second adhesive layer, and a sealant layer laminated sequentially on one surface of a base material layer, wherein the coating layer is a multilayer structure comprising a layer (A), in which 1 to 100 parts by mass of a phosphoric acid or a phosphate has been blended into 100 parts by mass of a rare earth element-based oxide, and a layer (X) which contains an anionic polymer and a cross-linking agent that causes cross-linking of the anionic polymers.

1. A packing material for a lithium cell, comprising a first adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer or a second adhesive layer, and a sealant layer laminated sequentially on one surface of a base material layer, wherein
 the coating layer is a multilayer structure comprising a layer (A), in which 1 to 100 parts by mass of a phosphoric acid or a phosphate has been blended into 100 parts by mass of a rare earth element-based oxide, and a layer (X) containing an anionic polymer and a cross-linking agent that causes cross-linking of the anionic polymers, and 
 a relationship between a mass (a) per unit surface area (g/m 2 ) of the layer (A), and a mass (x) per unit surface area (g/m 2 ) of the layer (X) satisfies an expression 2≧x/a≧0.01. 
 
     
     
       2. A packing material for a lithium cell according to  claim 1 , wherein the layer (A) is laminated directly onto the aluminum foil layer. 
     
     
       3. A packing material for a lithium cell according to  claim 1 , wherein a mass (a) per unit surface area (g/m 2 ) of the layer (A) is within a range from 0.010 to 0.200 g/m 2 . 
     
     
       4. A packing material for a lithium cell according to  claim 1 , wherein the coating layer is the multilayer structure further comprising a layer (Y) containing a cationic polymer and a cross-linking agent that causes cross-linking of the cationic polymers. 
     
     
       5. A packing material for a lithium cell according to  claim 4 , wherein a relationship among a mass (a) per unit surface area (g/m 2 ) of the layer (A), a mass (x) per unit surface area (g/m 2 ) of the layer (X), and a mass (y) per unit surface area (g/m 2 ) of the layer (Y) satisfies an expression 2≧(x+y)/a>0.01. 
     
     
       6. A packing material for a lithium cell, comprising a first adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer or a second adhesive layer, and a sealant layer laminated sequentially on one surface of a base material layer, wherein
 the coating layer comprises a layer (M) containing a rare earth element-based oxide, a phosphoric acid or a phosphate, an anionic polymer, and a cross-linking agent that causes cross-linking of the anionic polymers, in which 
 1 to 100 parts by mass of the phosphoric acid or the phosphate has been blended into 100 parts by mass of the rare earth element-based oxide, and 
 the coating layer (M) composition has a relationship that satisfies an expression 2≧x′/a′≧0.01 between a total mass (a′) (g) of the rare earth element-based oxide and the phosphoric acid or the phosphate, and a total mass (x′) (g) of the anionic polymer and the cross-linking agent that causes cross-linking of the anionic polymers. 
 
     
     
       7. A packing material for a lithium cell according to  claim 6 , wherein the coating layer is the multilayer structure further comprising a layer (Y) containing a cationic polymer and a cross-linking agent that causes cross-linking of the cationic polymers. 
     
     
       8. A packing material for a lithium cell according to  claim 4  or  7 , wherein the cationic polymer is at least one polymer selected from the group consisting of polyethyleneimines, ionic polymer complexes made of a polyethyleneimine and a polymer having carboxylic acid groups, primary amine-grafted acrylic resins having a primary amine grafted to a main acrylic backbone, polyallylamines and derivatives thereof, and aminophenols. 
     
     
       9. A packing material for a lithium cell according to  claim 1  or  6 , wherein the anionic polymer is a copolymer comprising, as a main component, poly(meth)acrylic acid or a salt thereof, or (meth)acrylic acid or a salt thereof. 
     
     
       10. A packing material for a lithium cell according to any one of  claims 1 ,  4 ,  6 , and  7 , wherein the cross-linking agent is at least one material selected from the group consisting of compounds having an isocyanate group, a glycidyl group, a carboxyl group or an oxazoline group as a functional group, and silane coupling agents. 
     
     
       11. A packing material for a lithium cell according to  claim 1  or  6 , wherein the rare earth element-based oxide is cerium oxide. 
     
     
       12. A packing material for a lithium cell according to  claim 1  or  6 , wherein the phosphoric acid or phosphate is a condensed phosphoric acid or a condensed phosphate. 
     
     
       13. A packing material for a lithium cell according to  claim 1  or  6 , wherein the adhesive resin layer is composed of (i) or (ii) below, and the second adhesive layer is composed of (iii) below:
 (i) an acid-modified polyolefin-based resin (α), 
 (ii) a resin composition in which an acid-modified polyolefin-based resin (α) (30 to 99% by mass) is combined with an isocyanate compound or derivative thereof (β) and a silane coupling agent (γ)((β)+(γ): 1 to 70% by mass), provided that if (β)+(γ) is deemed to be 100, then (β):(γ) =10 to 90:90 to 10, and 
 (iii) a polyurethane-based adhesive comprising a polyol component as a main component, and an isocyanate compound or derivative thereof as a curing agent. 
 
     
     
       14. A production method for a packing material for a lithium cell, comprising sequentially laminating a first adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer or a second adhesive layer, and a sealant layer on one surface of a base material layer, wherein
 the coating layer is laminated on top of the aluminum foil layer by
 applying a coating composition (A), which comprises a rare earth element-based oxide and 1 to 100 parts by mass of a phosphoric acid or a phosphate per 100 parts by mass of the rare earth element-based oxide, onto the aluminum foil layer and subsequently drying the coating composition (A) to form a layer (A); and 
 applying a coating composition (X), which comprises an anionic polymer and a cross-linking agent that causes cross-linking of the anionic polymers, onto the layer (A) and subsequently drying the coating composition (X) to form a layer (X), 
 wherein a relationship between a mass (a) per unit surface area (g/m 2 ) of the layer (A), and a mass (x) per unit surface area (g/m 2 ) of the layer (X) satisfies an expression 2>x/a≧0.01. 
 
 
     
     
       15. A production method for a packing material for a lithium cell according to  claim 14 , wherein the coating layer is laminated on top of the aluminum foil layer by further applying a coating composition (Y), which comprises a cationic polymer and a cross-linking agent that causes cross-linking of the cationic polymers, onto the layer (A) or the layer (X), and subsequently drying the coating composition (Y) to form a layer (Y). 
     
     
       16. A production method for a packing material for a lithium cell, comprising sequentially laminating a first adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer or a second adhesive layer, and a sealant layer on one surface of a base material layer, wherein
 the coating layer is laminated on top of the aluminum foil layer by applying a coating composition (M), which comprises a rare earth element-based oxide, 1 to 100 parts by mass of a phosphoric acid or a phosphate per 100 parts by mass of the rare earth element-based oxide, an anionic polymer, and a cross-linking agent that causes cross-linking of the anionic polymers, onto the aluminum foil layer and subsequently drying the coating composition (M) to form a layer (M), and 
 the coating composition (M) has a relationship that satisfies an expression 2≧x′/a′≧0.01 between a total mass (a′) (g) of the rare earth element-based oxide and the phosphoric acid or the phosphate, and a total mass (x′) (g) of the anionic polymer and the cross-linking agent that causes cross-linking of the anionic polymers. 
 
     
     
       17. A production method for a packing material for a lithium cell according to  claim 16 , wherein the coating layer is laminated on top of the aluminum foil layer by further applying a coating composition (Y), which comprises a cationic polymer and a cross-linking agent that causes cross-linking of the cationic polymers, onto the layer (M), and subsequently drying the coating composition (Y) to form a layer (Y). 
     
     
       18. A production method for a packing material for a lithium cell according to  claim 17 , wherein the coating composition (M) and the coating composition (Y) have a relationship that satisfies an expression 2≧(x′+y′)/a′>0.01 among a total mass (a′) (g) of the rare earth element-based oxide, and the phosphoric acid or the phosphate, a total mass (x′) (g) of the anionic polymer and the cross-linking agent that causes cross-linking of the anionic polymers, and a total mass (y′) (g) of the cationic polymer and the cross-linking agent that causes cross-linking of the cationic polymers.